A known actuator apparatus of which a drive source is a motor may include an electromagnetic clutch which can selectively connect and disconnect a transmission path of a motor torque. For example, according to an actuator apparatus described in Patent reference 1, an electromagnetic clutch apparatus includes an armature and a rotor. The armature is supported by a drive member rotated by a motor drive and rotates integrally with the drive member, and the armature is provided to be movable in an axial direction. The rotor is arranged coaxially with the armature to be rotatable relative to the armature and rotates integrally with an output member. By making the armature and the rotor to be in pressure contact with each other in accordance with an electromagnetic attractive force generated by an electromagnet thereof, the two rotating bodies (the armature and the rotor) can be connected to each other in such a manner that torque of a motor is transmittable.
In addition, the actuator apparatus includes an accommodation member accommodating a speed reduction mechanism and the electromagnetic clutch. According to the known art, a worm wheel (a wheel gear) constituting the speed reduction mechanism serves as the drive member supporting the armature in such a manner that the armature is movable in the axial direction while rotating integrally, as described above.